CAN, LIN, whatever. It's not my field of expertise so I wouldn't presume to suggest what type of data bus to use. I'd guess whichever bus technology is used, it'll need two conductors then another two for power. So for anything that uses 4 conductors or less, like a single stepper or filament monitor, then a (local) module would be pretty pointless. But for say a hot end carriage, that has a heater, fan, temperature sensor, a Z probe, probably part cooling fan(s), possible lights, possibly axis limit switches etc, then a local module fixed to the carriage say, makes a lot of sense. For sure it'll take a bit of space but on the gantry/carriage, not the hot end itself. Any extra weight would likely be compensate for by only needing short conductors between the module and components with just data and power going back to a central point. Of course with Delta printers, everything is a lot more compact and it's relatively easy to fit the electronics close to all the stepper motors, which themselves are all close together but for those of use with motors scattered around a large frame, running all the conductors back to a central point can be a bit of a nightmare.
Anyway, enough of my ramblings and apologies for going off topic.
